Clean air per specifications is needed in areas and volumes where the activities undertaken will not be assuredly successful, unless clean air meeting certain specifications is the only air passing through the volume or locale where the activity is being undertaken. Many types of equipment are offered in the marketplace and are disclosed in patents and publications, which supply clean air to meet various specifications. Some of these types are portable for convenient use at a specific locale where clean air is needed, and often the locale is designated as an ultra clean air zone.
In respect to equipment illustrated and described in U.S. Patents:
In 1974, Messrs. Anspach Jr. and Bakels in their U.S. Pat. No. 3,820,536, disclosed their portable apparatus for providing clean air at a surgical area. Air from a nearby surrounding area was drawn in at the height of an operating table, then filtered, and thereafter discharged horizontally over the operating table and past the patient. Sterile drapes were used to continue the direction of the clean air and to avoid the entry of non-filtered air into the stream of the filtered clean air;
In 1976, Louis Bush in his U.S. Pat. No. 3,935,803 described and illustrated his air filtration apparatus, which was portable, and at its place of use about a hospital bed, it directed a filtered stream of clean air downwardly over the entire bed. The surrounding room air entered just above floor level beyond the head of the bed, and then the air was filtered enroute upwardly to be discharged from a cantilevered plenum chamber positioned over the hospital bed;
In 1985, Frederick H. Howorth in his U.S. Pat. No. 4,531,956, disclosed his sterile air trolley, movable to a locale where sterile air was required. Surrounding air to be cleaned and sterilized was drawn in horizontally through filters, and then moved upwardly by a blower to enter a horizontal casing having many discharge openings, arranged in both vertical and horizontal planes. The principal quantity of the sterile air was directed downwardly through a volume or locale, where an activity was underway, which was being performed when surrounded by the downwardly flowing sterile air, which remained free of any contaminated ambient air;
In 1988, Charles W. Spengler in his U.S. Pat. No. 4,732,592 illustrated and described his portable clean air facility having a powered filtering unit to draw in surrounding air, and also to draw in air leaving the adjacent clean air volume surrounded by plastic sheeting draped over P.V.C. pipe framing, and then to discharge the filtered air downwardly through this adjacent clean air volume; and
In 1994 Raine Riutta described and illustrated in U.S. Pat. No. 5,312,465 a filtration apparatus with bag-like plenum chamber, which is portable and collapsible for movement and storage, and then inflated, in part, when in use. Surrounding air is drawn in just above floor level and then directed upwardly while being filtered. Thereafter, the filtered air enters the then inflated flexible bag, serving as a plenum chamber, which extends first on a diagonal to a higher elevation, and then in a horizontal plane to position an outlet at the end of this inflated plenum chamber above a locale where clean air is needed. The filtered clean air is thereafter directed downwardly to and through the locale requiring the flow of clean air.
In respect to equipment available in the marketplace and set forth in published information, the model Clas 10 portable clean air station produced by the International Portland Corporation, is illustrated and described as a portable unit which draws surrounding air in just above floor level for entering a pre-filter. Thereafter the pre-filtered air is directed upwardly through an adjustable height vertical tube which, at its top, is connected to a fixed ninety degree elbow. Then this elbow is connected to a horizontal tube. At the extended end of this horizontal tube is an attached angular adjustment mechanism surrounded by a bellows, which is also secured to the horizontal tube. Both the angular adjustment mechanism and the bellows are also connected, at their other ends, to an adjustable head having a plenum and a HEPA filter. The pre-filtered air passes from the tubes, to pass by the angular adjustment mechanism, while being directed within the bellows. Then the pre-filtered air enters the plenum and passes through the HEPA filter to be discharged as clean air through the adjustable head, in a selected direction through a locale where flowing clean air is needed. This adjustable head is tiltable through ninety degrees, and by movement of this portable clean air station, it is positioned through three hundred and sixty degrees. The angular position of the adjustable head, when changed, requires the manipulation of an external locking and unlocking knob accessible on the outside top of the horizontal tube.
The arrangement of the model Clas 10 portable clean air station allows the pre-filtered air to enter the center of the filter plenum of the adjustable head. When the adjustable head is positioned horizontally, the clean air leaves in a downward vertical airflow, as this adjustable head is located at an extended distance from the vertical tube.
In respect to this extended distance, the bellows is located 1.5 times the width or size of the filter off of the centerline of the vertical tube. Therefore, when moving this Clas 10 portable clean air station, this unbalanced top heavy configuration requires very careful handling during the movements thereof. The adjustable head and the filter thereof are not sufficiently adjustable to be taken out of this unbalanced extended position during any movement of this Clas 10 portable clean air station. Although all these illustrated and described products are recognized for their merits and for their production of clean air and/or sterile air, which is directed through locales needing only the flow of such clean and/or sterile air, there remains several unfulfilled needs for portable equipment to supply and to conveniently deliver clean and/or sterile air.